Lai

This research focuses on the application of negative thermal expansion (NTE) materials in advanced electronic packaging, with zirconium vanadate (ZrV₂O₇) selected as the primary material system.

As semiconductor packaging technologies continue to develop toward higher integration density, miniaturization, and multilayer stacking, the mismatch in coefficient of thermal expansion (CTE) among different packaging materials has become a critical reliability issue. During thermal processes such as reflow soldering, thermal cycling, or device operation, materials including silicon chips, copper micro-bumps, substrates, and underfill expand or contract to different extents. This thermal expansion mismatch can induce thermal stress accumulation, leading to package warpage, interfacial delamination, crack formation, and reduced long-term reliability.

Underfill is an essential encapsulation material filled between the chip and the substrate. It provides mechanical support, redistributes stress, and enhances package reliability. However, conventional epoxy-based underfill materials generally exhibit relatively high CTE values, which may further intensify the thermal mismatch between different components. Therefore, effective control of the overall CTE of underfill materials is a key strategy for mitigating warpage and improving the thermomechanical reliability of advanced packaging structures.

In this study, ZrV₂O₇, which exhibits negative thermal expansion behavior, is introduced as a functional filler into the underfill system. The objective is to reduce and tailor the overall CTE of the underfill composite, allowing it to better match the thermal expansion behavior of silicon chips, substrates, and other packaging components. By improving thermomechanical compatibility among different materials, thermal stress concentration can be effectively reduced, thereby minimizing warpage and interfacial failure risks.

Overall, this research not only investigates the synthesis and property analysis of ZrV₂O₇-based NTE materials, but also evaluates their potential application as functional fillers in epoxy-based underfill systems for CTE regulation, warpage suppression, and reliability enhancement in advanced electronic packaging.